JP5969205B2 - Negative pressure pump - Google Patents

Description

  The present invention relates to a negative pressure pump, for example, a negative pressure pump that makes negative pressure in a negative pressure chamber of a negative pressure booster provided in a vehicle.

  As a kind of negative pressure pump, a vacuum pump that generates a negative pressure by a vaned rotor has been proposed (see, for example, Patent Document 1 (FIG. 1)).

The technique of this patent document 1 is demonstrated below based on drawing.
FIG. 19 is a cross-sectional view of a conventional vacuum pump 200. When the vane 201 is rotated, air is sucked into the housing 203 from the intake port 202, and the air pressurized by the vane 201 is passed through the discharge port 204 to be a silencer chamber. It is discharged to 205. The sound deadening chamber 205 has a sufficiently large space, and the compressed air is discharged from the discharge port 204 into the large space to expand. Air suddenly expands and consumes acoustic energy. The silenced air is exhausted through the silencer pipe 206.

A silencer 207 provided with a silencer chamber 205 is connected to the housing 203 via a gasket 208 and fixed with bolts.
The sound deadening chamber 205 has the same width as the housing 203 and is sufficiently large. Therefore, the vacuum pump 200 becomes large.
In recent years, miniaturization and weight reduction of in-vehicle components are required, and miniaturization is required even for a vacuum pump having a silencing chamber or a silencing function.

Japanese Utility Model Publication No.59-13685

  This invention makes it a subject to provide the pump structure which can be reduced in size even if it is a vacuum pump provided with a silencing room or a silencing function.

The invention according to claim 1 includes a body portion as a base, a pump portion attached to one side surface of the body portion, and a cover attached to one side surface of the body portion having a storage chamber surrounding the pump portion. In the negative pressure pump comprising a rotor, a case surrounding the rotor, and a lid that closes the opening of the case, an exhaust gas is provided to at least one of the body portion and the cover body. A silencer chamber for attenuating sound is formed separately from the storage chamber, and the exhaust from the pump section flows in the order of the storage chamber, the communication path connecting the storage chamber and the silencer chamber, and the silencer chamber in this order. The exhaust sound is discharged to the outside through the exhaust pipe, and the exhaust sound is attenuated in the silencer chamber, and the silencer chamber is provided between the body part and the cover body, and the communication path is formed in the body part. that are provided And features.

In the invention which concerns on Claim 2, it has the body part as a base | substrate, the pump part attached to one side surface of this body part, and the cover which has a storage chamber surrounding this pump part and is attached to one side surface of the said body part In the negative pressure pump comprising a rotor, a case surrounding the rotor, and a lid that closes the opening of the case, an exhaust gas is provided to at least one of the body portion and the cover body. A silencer chamber for attenuating sound is formed separately from the storage chamber, and the exhaust from the pump section flows in the order of the storage chamber, the communication path connecting the storage chamber and the silencer chamber, and the silencer chamber in this order. The exhaust sound is exhausted through the exhaust pipe, and the exhaust sound is attenuated in the noise reduction chamber in the meantime. An extension pipe portion extending to the noise reduction chamber is provided in the exhaust pipe, and a number of fine holes are provided in the extension pipe portion. , These micropores Wherein the exhaust was set to resonate.

  The invention according to claim 3 is characterized in that an inner wall is provided inside the cover body, a space between the inner wall and the outer wall of the cover body is formed as a sound deadening chamber, and the communication path is formed through the inner wall of the cover body. .

The invention according to claim 4 is characterized in that the exhaust pipe is provided with an extension pipe portion extending to the sound deadening chamber, and a plurality of fine holes are provided in the extension pipe portion, and the exhaust is resonated by these fine holes. To do.
In the invention according to claim 5 , the lid is provided with an exhaust outlet for allowing exhaust to flow into the housing chamber from the inside of the pump portion, and a pipe-shaped lead-out pipe is extended from the exhaust outlet into the housing chamber, and the exhaust gas discharged from the lead-out pipe is discharged. It is characterized by being rapidly expanded in the storage chamber.

In the invention according to claim 1, a silencer chamber for attenuating exhaust sound is formed in at least one of the body part and the cover body separately from the accommodation room, and the exhaust from the pump part is contained in the accommodation room, the accommodation room and the silencer. It flows in the order of the communication path connecting to the chamber and the muffler chamber, and is discharged outside through the exhaust pipe.
Since the sound deadening chamber is formed in at least one of the body part and the cover body, the sound deadening chamber can be built in the negative pressure pump, and the pump structure can be downsized even with a sound deadening chamber or a vacuum pump having a sound deadening function. can do.

In addition, in the invention according to claim 1 , the muffler chamber is provided between the body portion and the cover body, and the communication path is provided in the body portion.
A silencer chamber is provided between the body part and the cover body without using any separate parts, and the communication path is formed simply by drilling the body part. Therefore, a silencer room that can obtain a noise reduction effect without increasing the number of parts is provided. This can reduce the cost of parts.
In the invention according to claim 2, the exhaust pipe is provided with an extension pipe portion extending to the sound deadening chamber, and the extension pipe portion is provided with many fine holes.
Since a large number of fine holes are provided in the extension pipe portion, the exhaust can be resonated by these fine holes, and the silencing effect can be further enhanced.

  In the invention which concerns on Claim 3, the inner wall was provided in the inside of a cover body, the space of an inner wall and the outer wall of a cover body was formed as a muffling chamber, and the communicating path was penetrated and formed in the inner wall of the cover body. Since the sound deadening chamber is formed in the cover body and the communication passage is formed through only the inner wall of the cover body, only the cover body needs to be processed, and the cost can be further reduced.

In the invention which concerns on Claim 4, the extension pipe part extended to a sound deadening chamber was provided in the exhaust pipe, and many fine holes were provided in this extension pipe part.
Since a large number of fine holes are provided in the extension pipe portion, the exhaust can be resonated by these fine holes, and the silencing effect can be further enhanced.
In the invention according to claim 5 , the lid body is provided with an exhaust outlet through which exhaust gas flows from the inside of the pump section into the accommodating chamber, and a pipe-shaped outlet pipe is extended from the exhaust outlet into the accommodating chamber.
Since the pipe-shaped lead-out pipe is provided on the lid, the exhaust gas discharged from the lead-out pipe can be rapidly expanded in the storage chamber, and a silencing effect can be obtained even in the storage chamber.

It is a figure which shows the example of arrangement | positioning of the negative pressure pump which concerns on this invention. It is a perspective view of a negative pressure pump. It is a fragmentary sectional view of a negative pressure pump. It is a disassembled perspective view of a negative pressure pump. It is a disassembled perspective view of a pump part. It is a front view of a negative pressure pump. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 6. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 7. FIG. 10 is a sectional view taken along line 10-10 in FIG. 8. It is the 11-11 line sectional view of FIG. It is a figure explaining the flow of the intake air from a connection pipe to a pump part. It is a figure explaining the flow of the exhaust_gas | exhaustion from a pump part to an exhaust pipe. It is a figure explaining discharge of water generated by dew condensation. It is a figure explaining the flow of the air to a breathing hole. It is a figure explaining the other aspect of FIG. It is a figure explaining the other aspect of FIG. It is a figure explaining the other aspect of FIG. It is a principle diagram of a conventional negative pressure pump.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

First, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the negative pressure pump 10 of the present invention is a kind of vacuum pump that makes negative pressure in a negative pressure chamber 12 of a negative pressure booster 11 provided in a vehicle.
When the negative pressure pump 10 is operated, the negative pressure pipe 13, the negative pressure chamber 12, and the variable pressure chamber 14 are at negative pressure. When the brake pedal 16 is depressed in this state, the negative pressure chamber 12 and the variable pressure chamber 14 are cut off, air is introduced into the variable pressure chamber 14, and the diaphragm 17 is returned to the return spring by the differential pressure between the negative pressure chamber 12 and the variable pressure chamber 14. 18 is deformed to the compression side and push rod 19 is pushed out. As a result, a large braking force can be obtained with a small pedal effort.

The internal structure of the negative pressure pump 10 will be described with reference to FIG. In FIG. 2, the external appearance of the negative pressure pump 10 will be described.
As shown in FIG. 2, a body portion 30 as a base, a cover body 50 is attached to the upper surface of the body portion 30, and a motor 70 is attached to the lower surface of the body portion 30. A connecting pipe 21 for intake is attached to the narrow surface 31 of the body portion 30 with screws 22, and a plurality of (three in this example) arm portions 32 are extended from the body portion 30, and a bush 33 is attached to the arm portion 32. Is fitted. The bush 33 serves as a rubber mount when attached to the vehicle.

Next, the inside of the negative pressure pump 10 will be described.
As shown in FIG. 3, a pump unit 80 that generates a negative pressure is attached to the upper surface of the body unit 30. The pump unit 80 is surrounded by a storage chamber 51 provided in the cover body 50. An inner wall 63 is provided inside the cover body 50, and a space between the inner wall 63 and the outer wall 52 of the cover body is formed as a sound deadening chamber 53.

Next, the structure of the negative pressure pump 10 will be described in detail.
As shown in FIG. 4, the negative pressure pump 10 includes a body portion 30 as a base, and a plurality of (four in this example) provided on the upper surface 34 (one side surface 34 in the present invention) of the body portion 30. The pump portion 80 attached by screwing a long bolt 81 into the female screw hole 35, the connection pipe 21 connected to the suction port (detailed later), the pump portion 80 and the upper surface 34 of the body portion 30 (in the present invention) A cover body 50 attached by screwing screws 54 into a plurality (four in this example) of female screw holes 36 provided on one side surface 34) and a lower surface 37 (the other side surface 37) of the body portion 30 A plurality of (in this example, two) screws 71 are attached, and the motor shaft 72 includes a motor 70 that is an involute spline shaft.

An intermediate connector (reference numeral 73 in FIG. 7) for supplying power to the motor 70 is provided on the side of the motor 70.
Since the body part 30 is a base for mounting the motor 70 and connecting to the vehicle, it is desirable that the body part 30 is made of a metal having a large thickness and rigidity, such as a casting. A shaft hole 38 into which the motor shaft 72 is inserted is provided at the center of the body portion 30.

  A part of the body portion 30 is formed with a silencer chamber 53 that is integral with the silencer chamber 53 of the cover body 50. A side surface of the body portion 30 to which the pump portion 80 is attached is referred to as an upper surface 34. A sealing material 41 is fitted along the outer periphery of the upper surface 34 and the outer periphery of the sound deadening chamber 53.

  Further, a semicircular intake groove 42 centering on the shaft hole 38 is provided on the upper surface 34 from the upper side to the lower side of the shaft hole 38, and a sealing material 43 such as an O-ring is provided so as to surround the intake groove 42. It is fitted on the upper surface 34.

  The cover body 50 has a shape in which an inclined portion 55 is provided in a part of a bottomed cylinder, a bottom portion 56 that faces the upper surface 34 of the body portion 30, and a cylindrical portion 57 that extends from the bottom portion 56 toward the upper surface 34. The flange portion 58 is formed at the end portion of the cylindrical portion 57 in a bowl shape.

  FIG. 5 is an exploded perspective view of the pump unit 80. The pump unit 80 includes a non-circular rotor chamber 82 and a case 84 provided with a plurality (four in this example) of bolt holes 83, and a plurality of vane grooves 85. Are provided radially, an involute spline hole 86 is provided at the center, a rotor 87 rotatably accommodated in a rotor chamber 82 having a non-circular cross section, and a vane 88 movably accommodated in a plurality of vane grooves 85, respectively. , An intake plate 94 having a plurality (four in this example) of bolt holes 91 and two upper and lower intake holes 92, 93, a plurality (four in this example) of bolt holes 96 and two upper and lower exhaust outlets 97. , 98 and a plurality of (four in this example) long bolts 81 that pass through the bolt holes 96, 83, 91.

  FIG. 6 is a front view of the negative pressure pump 10. The negative pressure pump 10 is provided on the upper surface 34 of the body portion 30 and generates a negative pressure (FIG. 4, reference numeral 80), and the upper surface 34 of the body portion 30. And a motor 70 that is provided on the lower surface 37 of the body portion 30 and drives the pump portion 80. Although details will be described later, the air sucked from the connection pipe 21 passes through the negative pressure pump 10 and is discharged from an exhaust pipe 111 extending downward from the body portion 30.

The internal structure of the negative pressure pump will be described in more detail based on FIGS.
FIG. 7 is a sectional view of the negative pressure pump 10 assembled based on FIGS. 4 and 5.
As shown in FIG. 7, a rolling bearing 102 is provided in the shaft hole 38, and the motor shaft 72 is supported by the bearing 102. The tip of the motor shaft 72 is fitted into the involute spline hole 86 of the rotor 87, and the tip reaches the vicinity of the lid 101.

The flange portion 58 of the cover body 50 is in contact with the entire circumference of the sealing material 41, and the sealing material 41 ensures airtightness in the cover body 50.
On the other hand, the surface of the intake plate 94 is in contact with the entire periphery of the sealing material 43, and the opening of the intake groove 42 is blocked by the sealing material 43 and the intake plate 94, thereby forming the intake passage 103. As a result, an intake path including the connection pipe 21, the intake port 24, the intake passage 103, and the two intake holes (FIG. 5, reference numerals 92 and 93) is formed.

  On the other hand, the exhaust from the exhaust outlets 97 and 98 of the pump unit 80 is discharged into the storage chamber 51. A space between the storage chamber 51 and the pump unit 80 forms a part of the exhaust path 104. This exhaust path 104 also appears in FIG.

  As shown in FIG. 8, the exhaust path 104 through which the exhaust from the exhaust outlets 97 and 98 passes, the space between the cover body 50 and the pump unit 80 in the storage chamber 51, and the storage chamber 51 and the muffler chamber 53. The communication path 105 to be connected, the muffler chamber 53, a recess 61 provided in the bottom 59 of the muffler chamber 53, and an exhaust pipe 62 connected to the recess 61. The communication path 105 is provided in the body part 30.

Next, one side surface 34 of the body part 30 will be described.
As shown in FIG. 9, a breathing hole 121 for supplying air from the vicinity of the motor shaft 72 to the motor (FIG. 7, reference numeral 70) is provided on one side surface 34 of the body portion 30 at a position away from the exhaust path 104. It is done. The breathing hole 121 is provided for supplying air to the motor 70 to prevent the inside of the motor 70 from being evacuated.

  In addition, a communication path 122 that guides air from the exhaust path 104 to the breathing hole 121 is provided on one side surface 34. The communication path 122 includes a bottom surface portion 123, a barrier 124 that is one step higher than the bottom surface portion 123, and a top surface portion 125 that is one step higher than the barrier 124 and closely contacts the intake plate (see reference numeral 94). Further, the communication path 122 has a meandering shape when viewed from the pump unit (FIG. 7, reference numeral 80) side.

Next, the exhaust path 104 will be described based on a cross-sectional view taken along the axis of the communication path 105.
As shown in FIG. 10, the body 30 is provided with a storage chamber side recess 126 that is recessed downward on the upper surface 34 that forms the storage chamber 51. The communication path 105 is provided at the lowest position of the accommodation chamber side recess 126. The communication path 105 connects the storage chamber side recess 126 and the muffler chamber 53 and is inclined downward from the left to the right in the figure. The communication path 105 is formed by drilling the narrow surface 31 of the body portion 30, and the opening is closed with a steel ball 127.

Next, the silencer 53 will be described.
As shown in FIG. 11, a communication path 105 is provided in the muffler chamber 53. The muffler chamber 53 is a space surrounded by the cover body 50 and the bottom 59 of the muffler chamber provided in the body part 30. A recess 61 that is recessed downward is provided at the bottom 59 of the sound deadening chamber, and an exhaust pipe 62 of the recess 61 is connected. The bottom 59 of the silencer is inclined downward from the communicating part of the communication path 105 toward the right in the figure. That is, the concave portion 61 is provided at the lowest position of the silencing of the bottom 59, an exhaust pipe 62 extending from the recess 61 downwardly is provided.

Next, the silencing action of the negative pressure pump 10 will be described.
As shown in FIG. 12, when the motor (FIG. 7, reference numeral 70) operates, the outside air is sucked into the connection pipe 21 by the suction action of the pump unit 80. This intake air is drawn into the suction port 24 (arrow (1)).

  The intake air that has entered the intake port 24 enters the pump unit 80 through the intake hole 92 and is pressurized and discharged from the exhaust outlet 97 (arrow (2)), or is pumped from the intake hole 93 through the intake passage 103. Part 80 is pressurized and discharged from the exhaust outlet 98 (arrow (3)). Exhaust gas discharged from the upper and lower exhaust outlets 97 and 98 flows into the storage chamber 51.

  As shown in FIG. 13, the air compressed by the pump unit 80 is discharged into the storage chamber 51. This exhaust gas is guided to the communication path 105, is discharged to the muffler chamber 53 through the communication path 105, and rapidly expands (arrows (4), (5), (6)). Air suddenly expands and consumes acoustic energy. The silenced exhaust is discharged from the exhaust pipe 62 into the lower atmosphere (arrow (7)).

Next, the drainage action of the negative pressure pump 10 will be described.
As shown in FIG. 14A, water generated by condensation in the negative pressure pump 10 falls on the upper surface 34. The water that has fallen on the upper surface 34 flows from the accommodation chamber side recess 126 through the communication path 105 to the muffler chamber 53 (arrow (8)). As shown in (b), the water that has passed through the communication path 105 flows through the bottom 59 of the muffler chamber (arrow (9)), is collected in the recess 61, and is discharged downward from the exhaust pipe 62 (arrow (10). )).

Next, the action of removing the abrasion powder of the negative pressure pump 10 will be described.
As shown in FIG. 15, a rotating body (vane 88 and rotor 87) is built in the pump unit (FIG. 5, reference numeral 80), and since this rotating body is in sliding contact with the wall, a slight amount of wear powder is generated. . The abrasion powder is mixed with the exhaust gas and flows into the exhaust passage 104 and further flows into the communication passage 122. The wear powder is prevented from flowing into the communication passage 122 by the barrier 124 and the upper surface portion 125 (arrow (11)). The wear powder that has passed over the barrier 124 near the entrance of the communication passage 122 is prevented from flowing into the back by the barrier 124 and the upper surface portion 125 in the middle because the communication path 122 meanders (arrow (12)). (13)). The air from which the wear powder has been removed flows from the breathing hole 121 to the vicinity of the motor shaft 72 (arrow (14)) and is supplied into the motor (FIG. 7, reference numeral 70). A communication path 122 is provided while communicating from the exhaust path 104 to the breathing hole 121 of the motor, and the breathing hole 121 is the highest position in the communication path 122. Since the breathing hole 121 is at the highest position in the communication path 122, it is possible to prevent water from entering the motor 70.

Next, another aspect of FIG. 10 will be described. In addition, about the part which is common in FIG. 10, a code | symbol is diverted and description is abbreviate | omitted.
As shown in FIG. 16, an inner wall 63 is provided inside the cover body 50, and a space between the inner wall 63 and the outer wall 52 of the cover body 50 is formed as a muffler chamber 53. The communication path 131 is formed through the inner wall 63 of the cover body 50. By providing the communication path 131 in the cover body 50, the processing of the body part 30 can be reduced, and the processing cost of the body part 30 can be reduced.

Next, another aspect of FIG. 7 will be described. In addition, about the part which is common in FIG. 7, a code | symbol is diverted and description is abbreviate | omitted.
As shown in FIG. 17, exhaust outlets 97 and 98 for allowing exhaust to flow into the storage chamber 51 from the pump unit 80 are provided in the lid body 101. From these exhaust outlets 97 and 98, pipe-like outlet pipes 132 and 133 are extended into the storage chamber 51. The air compressed by the pump unit 80 is discharged from the outlet pipes 132 and 133 and is rapidly expanded in the storage chamber 51 to consume acoustic energy. As a result, the silencing effect can be improved even in the storage chamber 51.

Next, another aspect of FIG. 11 will be described. In addition, about the site | part which is common in FIG. 11, a code | symbol is diverted and description is abbreviate | omitted.
As shown in FIG. 18, in the body part 30, an extension pipe part 134 extending to the muffler chamber 53 is provided in the exhaust pipe 62. A plurality of fine holes 135 are provided in the extension pipe portion 134. The exhaust holes can be resonated by the fine holes 135, and the silencing effect can be improved.

According to the negative pressure pump acting as described above, the following effects can be obtained.
As shown in FIG. 13, a muffler chamber 53 for attenuating exhaust sound is formed in at least one of the body portion 30 and the cover body 50 separately from the storage chamber 51, and exhaust from the pump portion 80 is stored in the storage chamber 51, The communication passage 105 connecting the storage chamber 51 and the silencing chamber 53 flows in the order of the silencing chamber 53 and is discharged to the outside through the exhaust pipe 62.
According to this configuration, since the silencing chamber 53 is formed in at least one of the body portion 30 and the cover body 50, the silencing chamber 53 can be built in the negative pressure pump 10, and the silencing chamber 53 or a vacuum pump having a silencing function is provided. Even if it is 10, it can be set as the pump structure which can be reduced in size.

As shown in FIG. 10, the silencer chamber is provided between the body part 30 and the cover body 50, and the communication path 105 is provided in the body part 30.
According to this configuration, the muffler chamber 53 is provided between the body part 30 and the cover body 50 without using any separate parts, and the communication path 105 is formed only by drilling the body part 50, thereby increasing the number of parts. Therefore, it is possible to provide a silencing chamber 53 that can obtain a silencing effect without reducing the cost of components.

  As shown in FIG. 16, an inner wall 63 is provided inside the cover body 50, a space between the inner wall 63 and the outer wall 52 of the cover body 50 is formed as a muffler chamber 53, and the communication path 131 penetrates the inner wall 63 of the cover body. Formed. Since the sound deadening chamber 53 is formed in the cover body 50 and the communication passage 131 is formed through only the inner wall 63 of the cover body 50, only the cover body 50 needs to be processed, and the cost can be further reduced.

As shown in FIG. 17, the lid body 101 is provided with exhaust outlets 97 and 98 through which exhaust flows into the storage chamber 51 from the pump portion 80, and pipe-like outlet pipes 132 and 133 are connected to the exhaust outlets 97 and 98. It extended into the storage chamber 51.
With this configuration, since the pipe-shaped lead-out pipes 132 and 133 are provided in the lid body 101, the exhaust gas discharged from the lead-out pipes 132 and 133 can be rapidly expanded in the storage chamber 51. Can be obtained.

As shown in FIG. 18, the exhaust pipe 62 is provided with an extension pipe part 134 extending to the sound deadening chamber 53, and the extension pipe part 134 is provided with many fine holes 135.
With this configuration, since a large number of the fine holes 135 are provided in the extension pipe portion 134, the exhaust can be resonated by these fine holes 135, and the noise reduction effect can be further enhanced.

In the embodiment, the vane pump is described as the negative pressure pump. However, the negative pressure pump is not limited to the vane pump.
Furthermore, the negative pressure pump of the present invention is suitable for a negative pressure pump for a vehicle for making the negative pressure chamber of a negative pressure booster provided in the vehicle negative pressure, but it is not intended to limit the application. However, it can be applied to general machines, general-purpose machines, and general equipment.

  The negative pressure pump of the present invention is suitable for a negative pressure pump for a vehicle for making negative pressure inside a negative pressure chamber of a negative pressure booster provided in the vehicle.

  DESCRIPTION OF SYMBOLS 10 ... Negative pressure pump, 30 ... Body part, 34 ... One side surface (upper surface), 50 ... Cover body, 51 ... Storage chamber, 52 ... Outer wall, 53 ... Silencer chamber, 62 ... Exhaust pipe, 63 ... Inner wall, 80 ... Pump part, 84 ... case, 87 ... rotor, 97, 98 ... exhaust outlet, 101 ... lid body, 105, 131 ... communication path, 132, 133 ... extraction pipe, 134 ... extension pipe part, 135 ... micropore.

Claims (5)

A body portion as a base, a pump portion attached to one side surface of the body portion, and a cover body having a storage chamber surrounding the pump portion and attached to one side surface of the body portion, The pump section is a negative pressure pump comprising a rotor, a case surrounding the rotor, and a lid for closing the opening of the case.
A silencer chamber for attenuating exhaust sound is formed in at least one of the body portion and the cover body separately from the storage chamber,
Exhaust gas from the pump section flows in the order of the storage chamber, the communication path connecting the storage chamber and the muffler chamber, and the muffler chamber, and is discharged to the outside through an exhaust pipe. The exhaust sound is attenuated ,
The silencer chamber is provided between the body part and the cover body, and the communication path is provided in the body part . A body portion as a base, a pump portion attached to one side surface of the body portion, and a cover body having a storage chamber surrounding the pump portion and attached to one side surface of the body portion, The pump section is a negative pressure pump comprising a rotor, a case surrounding the rotor, and a lid for closing the opening of the case.
A silencer chamber for attenuating exhaust sound is formed in at least one of the body portion and the cover body separately from the storage chamber,
Exhaust gas from the pump section flows in the order of the storage chamber, the communication path connecting the storage chamber and the muffler chamber, and the muffler chamber, and is discharged to the outside through an exhaust pipe. The exhaust sound is attenuated ,
A negative pressure pump characterized in that an extension pipe portion extending to the muffler chamber is provided in the exhaust pipe, and a plurality of fine holes are provided in the extension pipe portion so that exhaust is resonated by these fine holes . The negative pressure pump according to claim 2 ,
An inner wall is provided inside the cover body, a space between the inner wall and the outer wall of the cover body is formed as the muffler chamber, and the communication path is formed through the inner wall of the cover body. pump. In the negative pressure pump according to claim 1 Symbol placement,
A negative pressure pump characterized in that an extension pipe portion extending to the muffler chamber is provided in the exhaust pipe, and a plurality of fine holes are provided in the extension pipe portion so that exhaust is resonated by these fine holes. The negative pressure pump according to any one of claims 1 to 4 ,
The lid body is provided with an exhaust outlet for allowing exhaust to flow into the housing chamber from the inside of the pump unit, and a pipe-shaped lead-out pipe extends from the exhaust outlet into the housing chamber, and the exhaust gas that has exited from the lead-out pipe is passed through the housing chamber. A negative pressure pump characterized by rapid expansion.

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